Integrated inertial sensing device

ABSTRACT

A system can include a MEMS gyroscope having a MEMS resonator overlying a CMOS IC substrate. The CMOS IC substrate can include an AGC loop circuit coupled to the MEMS gyroscope. The AGC loop acts in a way such that generated desired signal amplitude out of the drive signal maintains MEMS resonator velocity at a desired frequency and amplitude. A benefit of the AGC loop is that the charge pump of the HV driver inherently includes a ‘time constant’ for charging up of its output voltage. The system incorporates the Low pass functionality in to the AGC loop without requiring additional circuitry.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims priority to and incorporates byreference, for all purposes, the following patent applications: U.S.Provisional App. 61/755,450, filed Jan. 22, 2013, and U.S. ProvisionalApp. 61/755,451, filed Jan. 22, 2013.

BACKGROUND OF THE INVENTION

The present invention is directed to MEMS(Micro-Electro-Mechanical-Systems). More specifically, embodiments ofthe invention provide methods and structure for improving integratedMEMS devices, including inertial sensors and the like. Merely by way ofexample, the MEMS device can include at least an accelerometer, agyroscope, a magnetic sensor, a pressure sensor, a microphone, ahumidity sensor, a temperature sensor, a chemical sensor, a biosensor,an inertial sensor, and others. But it will be recognized that theinvention has a much broader range of applicability.

Research and development in integrated microelectronics have continuedto produce astounding progress in CMOS and MEMS. CMOS technology hasbecome the predominant fabrication technology for integrated circuits(IC). MEMS, however, continues to rely upon conventional processtechnologies. In layman's terms, microelectronic ICs are the “brains” ofan integrated device which provides decision-making capabilities,whereas MEMS are the “eyes” and “arms” that provide the ability to senseand control the environment. Some examples of the widespread applicationof these technologies are the switches in radio frequency (RF) antennasystems, such as those in the iPhone™ device by Apple, Inc. ofCupertino, Calif., and the Blackberry™ phone by Research In MotionLimited of Waterloo, Ontario, Canada, and accelerometers insensor-equipped game devices, such as those in the Wii™ controllermanufactured by Nintendo Company Limited of Japan. Though they are notalways easily identifiable, these technologies are becoming ever moreprevalent in society every day.

Beyond consumer electronics, use of IC and MEMS has limitlessapplications through modular measurement devices such as accelerometers,gyroscopes, actuators, and sensors. In conventional vehicles,accelerometers and gyroscopes are used to deploy airbags and triggerdynamic stability control functions, respectively. MEMS gyroscopes canalso be used for image stabilization systems in video and still cameras,and automatic steering systems in airplanes and torpedoes. BiologicalMEMS (Bio-MEMS) implement biosensors and chemical sensors forLab-On-Chip applications, which integrate one or more laboratoryfunctions on a single millimeter-sized chip only. Other applicationsinclude Internet and telephone networks, security and financialapplications, and health care and medical systems. As describedpreviously, ICs and MEMS can be used to practically engage in varioustype of environmental interaction.

Although highly successful, ICs and in particular MEMS still havelimitations. Similar to IC development, MEMS development, which focuseson increasing performance, reducing size, and decreasing cost, continuesto be challenging. Additionally, applications of MEMS often requireincreasingly complex microsystems that desire greater computationalpower. Unfortunately, such applications generally do not exist. Theseand other limitations of conventional MEMS and ICs may be furtherdescribed throughout the present specification and more particularlybelow.

From the above, it is seen that techniques for improving operation ofintegrated circuit devices and MEMS are highly desired.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to MEMS(Micro-Electro-Mechanical-Systems). More specifically, embodiments ofthe invention provide a system having an integrated MEMS gyroscopearchitecture. Embodiments described herein will cover various aspectsfor specific applications, but it will be recognized that the inventionhas a much broader range of applicability.

The present invention includes a device architecture for an integratedMEMS gyroscope system. This system architecture includes a MEMS block,which can be a single or multi-axis MEMS gyroscope element. The sensingelement is shown as capacitive but other sensing elements are alsopossible and the first amplifier interfacing with the MEMS element isdesigned appropriately. The MEMS gyroscope can include sense capacitorscoupled to a sense path and drive feedback capacitors coupled to a drivepath.

The gyroscope has a drive element that needs to resonate continuously atdesired frequency and amplitude. To maintain this oscillation of MEMSelement, the system includes a rectifier, comparator,Proportional-Integral-Derivative (PID) controller driver, which forms anAutomatic Gain Control (AGC) loop, according to an embodiment of thepresent invention. The driver shown as High Voltage (HV) in thearchitecture is ac or pulse voltage drive and can be low voltage (LV) orHigh Voltage (HV). Hereafter, we refer to the driver as HV driver but itmay be implemented as low voltage driver. The drive feedback capacitorsof the MEMS gyroscope can be coupled to a charge-sense-amplifier (CSA),which is coupled in series to a 90 degrees phase shifter (PS) and to therectifier.

In an embodiment, the system can also include a mixer configured as atransmission gate that is coupled to the MEMS gyroscope. A circuit loopincluding a digital low-pass-filter (LPF) coupled to a digital/analogconverter (DAC) can also be coupled to the mixer. In a specificembodiment, a temperature sensor can be configured with a phase shifter(PS) to compensate for phases changes due to temperature. The systemarchitecture can also include a test mode that allows measurement ofquadrature signal using blocks QD, comparator and multiplexer.

When the MEMS drive resonator generates signal at lower amplitude thandesired, the amplitude of the rectified signal from the CSA, used forprocessing signal from drive path as well as the sense path of thegyroscope, is smaller compared to the reference signal provided to thePID. The PID block generates output in Proportion to the difference ofthe input signals. The output of the PID block drives the charge pump.Output of PID block will be proportional to the difference in referencevoltage input to the PID and the rectified signal amplitude. If outputof PID is higher, then charge will provide larger voltage output.

The charge pump powers the HV driver block. If charge pump output ishigher, the HV driver outputs proportionally higher amplitude pulseswhich will inject more Force, proportional to product of dc and acvoltage output from HV driver, in to MEMS driver-resonator. Thedisplacement generated by the resonator is proportional to the inputforce and the Q of the resonator. E.g. larger the Q, larger is thedisplacement. Also, for a given Q, larger the force, larger is thedisplacement of MEMS drive element. Larger displacement of MEMS elementgenerates larger signal (for example as capacitance change). Thus, theAGC loop acts in a way that generated desired signal amplitude out ofthe drive signal and equivalently, maintains MEMS resonator velocity asdesired frequency and amplitude.

One of the benefits of proposed system architecture is that the chargepump, inherently includes a ‘time constant’ for charging up of itsoutput voltage. This incorporates the Low pass functionality in to theAGC loop without requiring additional circuitry. Various additionalobjects, features and advantages of the present invention can be morefully appreciated with reference to the detailed description andaccompanying drawings that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more fully understand the present invention, reference ismade to the accompanying drawings. Understanding that these drawings arenot to be considered limitations in the scope of the invention, thepresently described embodiments and the presently understood best modeof the invention are described with additional detail through use of theaccompanying drawings in which:

FIG. 1 is a simplified diagram illustrating a cross-sectional view of anintegrated MEMS gyroscope device according to an embodiment of thepresent invention.

FIG. 2 is a simplified block diagram illustrating a system having anintegrated MEMS gyroscope architecture according to an embodiment of thepresent invention.

FIG. 3 is a simplified block diagram illustrating a system having anintegrated MEMS gyroscope architecture according to an embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to MEMS(Micro-Electro-Mechanical-Systems).

More specifically, embodiments of the invention provide a system havingan integrated MEMS gyroscope architecture. Embodiments described hereinwill cover various aspects for specific applications, but it will berecognized that the invention has a much broader range of applicability.

FIG. 1 is a simplified diagram illustrating a cross-sectional view of anMEMS gyroscope device according to an embodiment of the presentinvention. The integrated MEMS gyroscope device 100 includes a substrate110 having a surface region 112, and a CMOS layer 120 overlying surfaceregion 112 of substrate 110. CMOS layer 120 has a CMOS surface region130. In some embodiments, CMOS layer 120 can include processed CMOSdevices in substrate 110 and can including multilevel metal interconnectstructures. The example shown in FIG. 1 includes six metal layers,M1-M6. The integrated MEMS gyroscope device 100 also includes a MEMSgyroscope 140 overlying the CMOS surface region, and includes anout-of-plane sense plate 121. Integrated MEMS gyroscope device 100 alsoincludes metal shielding within a vicinity of the MEMS device configuredto reduce parasitic effects. In the example of FIG. 1, metal regions 151and 152 are shields on the sides of the plate, while 153 is the shieldbelow the plate on metal 4. Those of ordinary skill in the art willrecognize other variations, modifications, and alternatives.

FIG. 2 is a simplified block diagram illustrating a system having anintegrated MEMS gyroscope architecture according to an embodiment of thepresent invention. Some included components are the Charge SenseAmplifiers (CSA), Programmable Gain Amplifier (PGA), Low Pass Filter(LPF), I2C. The CSAs is used for processing signals from the drive pathas well as sense path of a Gyroscope or other MEMS inertial sensingdevice. The I2C is a serial bus communication to digital registers onthe chip.

The MEMS block shown in FIG. 1 is a single or multi-axis MEMS gyroscopeelement. The sensing element is shown as capacitive but other sensingelements are also possible and the first amplifier interfacing with theMEMS element is designed appropriately.

The gyroscope has a drive element that needs to resonate continuously atdesired frequency and amplitude. To maintain this oscillation of MEMSelement, the drive loop consisting of CSA_DRV, phase shifter (PS0),comparator, HV driver provides gain of signal at desired frequency ofoscillation. The CSA_DRV senses the change in capacitance due to driveelement and converts it in to voltage signal.

In order to provide in-phase feedback signal, a 90 degree phase shifter,PS0, is added in the drive loop. The 90 degree phase shift can beimplemented as differentiator or integrator or other known techniques.

The Rectifier, comparator, Proportional-Integral-Derivative (PID)controller, High Voltage (HV) driver form an Automatic Gain Control(AGC) loop. When the MEMS drive resonator generates signal at loweramplitude than desired, the amplitude of the rectified signal from theCSA, used for processing signal from drive path as well as sense path ofGyroscope, is smaller compared to the reference signal provided to thePID. The PID block generates output in Proportion to the difference ofthe input signals. The output of the PID block drives the charge pump.Output of PID block will be proportional to the difference in referencevoltage input to the PID and the rectified signal amplitude. If outputof PID is higher, then charge will provide larger voltage output.

The charge pump powers the HV driver block. If charge pump output ishigher, the HV driver outputs proportionally higher amplitude pulseswhich will inject more Force, proportional to product of dc and acvoltage output from HV driver, in to MEMS driver-resonator. In aspecific embodiment, the HV driver can be implemented as a simpledigital gate. The power supply to the HV driver can be controlled usinga charge pump CP1, which effectively provides automatic gain controlledac pulses to the Gyro resonator. The HV driver can also be replaced by aconventional external supply (VDD) at any desired voltage, such as 1.8Vor others.

The displacement generated by the resonator is proportional to the inputforce and the Q of the resonator. E.g. larger the Q, larger is thedisplacement. Also, for a given Q, larger the force, larger is thedisplacement of MEMS drive element. Larger displacement of MEMS elementgenerates larger signal (for example as capacitance change). Thus, theAGC loop acts in a way that generated desired signal amplitude out ofthe drive signal and equivalently, maintains MEMS resonator velocity asdesired frequency and amplitude.

The PID block also provide a differential signal, which is necessary forkick-start of the AGC loop in order to pump up the charge pump outputfaster especially during power on. In the normal mode, an integratorintegrates the output of PID so that noise pulses do not cause undesiredchanges in the AGC path and makes the steady state error to be zero.

The rectifier, comparator, Proportional-Integral-Derivative (PID)controller, High Voltage (HV) driver, MEMS resonator, CSA_DRV and the 90degree phase shifter, PS0, form an Automatic Gain Control (AGC) loop.When the MEMS drive resonator generates signal at lower amplitude thandesired, the amplitude of the rectified signal from the CSA is smallercompared to the reference signal provided to the PID. The PID blockgenerates output in proportion to the difference of the input signals.The output of the PID block controls the gain of the HV driver, whichdecides the amplitude of the ac voltage, Vac, driving the MEMSresonator.

By driving the MEMS drive capacitors with an AC voltage that is of lowimpedance, dependence of the AGC loop performance on MEMS leakage can besubstantially eliminated. The displacement generated by the resonator isproportional to the input force and the Q of the resonator. E.g. largerthe Q, larger is the displacement. Also, for a given Q, the larger theforce, the larger is the displacement of MEMS drive element. Largerdisplacement of the MEMS element generates a larger signal (for exampleas capacitance change). Thus, the AGC loop acts in a way that generatesa desired signal amplitude out of the drive signal and equivalently,maintains MEMS resonator velocity as desired frequency and amplitude.

In a specific embodiment, the sensing mechanism of the gyroscope isbased on a Coriolis force, which is proportional to the vector productof angular rate of the gyroscope and the velocity of the MEMS driverresonator. The Coriolis force generates a displacement of the MEMS senseelement in a direction that is orthogonal to the drive velocity and theexternal angular rate. The displacement signal is sensed via a senseCharge Sense Amplifier (CSA). The signal at the output of the sense CSAwill have a carrier signal at the frequency of the resonance of thedrive resonator, which will be amplitude modulated by a signalproportional to the angular rate of motion.

The drive signal also gets injected in the sense path and is 90 degreesout of phase compared to the Coriolis displacement, and hence is termed“Quadrature coupling”. A programmable Quadrature cancellation DAC is anarray of programmable capacitors that allow a desired portion of thequadrature signal to be cancelled from the input signal. In addition, toaccurately cancel the quadrature, which may have a different phase than90 deg, a phase shifter PS1 is used in the present architectureembodiment.

The CSA-sense is a low noise amplifier with capacitive feedback. Inorder to maintain DC biasing at the amplifier input, a very highimpedance feedback at low frequency is required. In various embodimentsof the present invention, this configuration is realized by using MOStransistors operating in a sub-threshold region that can createimpedances in the order of Giga-ohms. The feedback to maintain inputcommon voltage is only desired at DC. In order to ensure little impactof the high impedance common mode feedback and to minimize noise impactat high frequency, a very low cut-off frequency low pass filter is addedin the feedback path.

The Programmable Gain Amplifier 1 (PGA1) amplifies the signal from CSAto a desired level. The rate signal needs to be demodulated from thesignal at the output of sense CSA. The mixer in the signal path achievesthe demodulation by mixing the carrier signal coming out from the driveCSA with the composite signal coming from the sense-CSA amplified by thePGA.

In a specific embodiment, the mixer is implemented as a transmissiongate. One input of the transmission gate is the pulse coming from thecomparator after going through the programmable phase shifter PS2. PhaseShifter PS2 shifts pulses by a programmable amount from −180 deg to +180deg thereby adjusting for both phase lead and lag between signal indrive loop verses signals in sense path.

In a specific embodiment, temperature compensation can be achieved byprogramming phase shifters PS1 and PS2 to be driven through aprogrammable serial interface based on temperature measured using anon-chip temperature sensor. Doing so will result in a demodulation andquadrature cancellation that is optimized with temperature. In anotherembodiment, temperature compensation loop for gyroscope that involves,reading chip temperature using on-chip Temp sensor via interface such asI2C. Processing of the temperature change can be done externally throughsoftware or hardware processor to come up with optimal correction thatcan be programmed back in to the chip using interface circuits such asI2C.

The Programmable Gain Amplifier PGA2 amplifies the demodulated ratesignal.

PGA2 also includes a Low Pass Filtering function. An embodiment of thepresent invention includes a LPF by simply adding a capacitor in thefeedback path of the PGA2. Since the carrier component is suppressedwith the LPF in the PGA2, the dynamic range can be effectively used fordesired rate signal amplification before converting to a digital domain.

A small phase shift with respect to 90 degrees may exist in the CSAdrive, which will generate DC or low frequency components afterdemodulation, thereby consuming dynamic range after the mixer. Accordingto a specific embodiment, a programmable phase shifter, PS2, can beconfigured within the architecture to effectively cancel this component.The PS coupled to the comparator can be used to adjust the phasedifference optimally to compensate for analog phase shifts and cancelout unwanted component of carrier (resonant) frequency.

According to another specific embodiment, a loop including or consistingof a digital low pass filter and DAC2 can be provided within thearchitecture. This loop cancels a small offset or low frequencycomponent that may exist in the signal path due to offsets of analogblocks or DC or low frequency components produced by the mixer that isnot in the range of rate signal frequency.

A high resolution (e.g. 16 bit) A/D converter (ADC) converts thedemodulated rate signal. The A/D converter has inputs for multiplechannels in order to multiplex the digital signal path for all of thechannels. One of the inputs of the A/D converter is from the on-chiptemperature sensor. The Temp sensor output can be effectively used tocompensate for the effect of the resonator variation with temperatureeither in the analog or digital domain. In an embodiment, thetemperature sensor output can be read and used to program the phaseshifter PS2 to compensate for changes in phase occurring due to changesin temperature. Temperature compensation can also be applied in thedigital path with certain programmability. Also, multiple axes (e.g.three axis for a 3 degrees of freedom (3DOF) Gyro) of the Gyro signalare multiplexed at the ADC.

The digital path can have signal processing such as programmable LowPass Filters to cancel noise outside of a band of interest. The digitalsignal path also has a programmable High Pass Filter (HPF) tosubstantially eliminate DC components, offset, or very low frequencyartifacts that are not within the expected rate signal band. In aspecific embodiment, the programmable HPF can be configured at afrequency using the DAC (DAC2) and a digital LPF in feedbackconfiguration.

The system architecture of FIG. 2 also shows a test mode that allowsmeasurement of quadrature signal using blocks QD, comparator andmultiplexer. In this embodiment, a voltage corresponding to the drivedisplacement is used to demodulate the signal form the MEMS sensecapacitors. This mode is multiplexed with the ‘normal’ mode in which thevoltage corresponding to the drive velocity is used to demodulate thesignal from the MEMS sense capacitors. The quadrature mode provides amethod to quantify the residual ‘feed-through’ or ‘quadrature’ signalfrom the MEMS drive capacitors to the sense capacitors, and to observehow it varies with ambient parameters such as temperature, humidity,etc.

In a specific embodiment, a digital delay, using block DELL isintroduced in the frequency control loop of the drive servo. Varying thedelay causes the loop to lock into different frequencies. For instance,the delay can be varied to make the loop lock into the 3-dB frequenciesof the MEMS drive resonator and measure the 3 dB bandwidth and qualityfactor.

FIG. 3 is a simplified block diagram illustrating a system having anintegrated MEMS gyroscope architecture according to another embodimentof the present invention. Similar to FIG. 2, the MEMS block shown inFIG. 3 is single or multi-axis MEMS gyroscope element. The sensingelement is shown as capacitive but other sensing elements are alsopossible and the first amplifier interfacing with the MEMS element isdesigned appropriately. Several of the components discussed for FIG. 2are also present in the embodiment depicted by FIG. 3. Thus, furtherinformation regarding of these components can be found in the previousdescriptions.

One of the benefits of proposed AGC loop is that the charge pump,inherently includes a ‘time constant’ for charging up of its outputvoltage. This incorporates the Low pass functionality in to the AGC loopwithout requiring additional circuitry.

The HV driver can be either analog HV amplifier or simple inverter. Thesupply voltage of HV driver is provided from charge pump CS1 andprovides one means of controlling the output amplitude from HV driver.

An additional charge pump, CS2, is designed to allow external powersupply voltage CP2 that can be lower compared to on-chip voltages. Forexample, the external power can be 1.8V and internal voltages can be3.3V and much higher voltages at charge pump for HV driver.

The multiple charge pump architecture allows more efficient usage ofpower. For example, the boosting of external supply voltage 1.8V mayhave to be boosted to 32V. This can be done as boost from 1.8V to 3.3Vand from 3.3V to 32V. This feature will allow usage of device at highervoltage to bypass one of the charge pumps CS2.

The layout of the Gyroscope MEMS and CMOS is very critical to achieveoptimal performance. All the out of plane sense signal plates areshielded with metal shield on sides (on same metal layer) as well as onlayers below the sense plates. In a specific embodiment, a shield may beplaced by skipping one or more metal layers to minimize parasiticcapacitance. For example, if sense plate is on metal 6, the shield maybe on metal 4 instead of metal 5 in order to provide more isolation &reduce parasitics. An example is shown in FIG. 1, which shows that CMOSlayer 120 can include processed CMOS devices (not shown) in substrate110 and can including multilevel metal interconnect structures, e.g.,six metal layers, M1-M6. The integrated MEMS gyroscope device 100 alsoincludes a MEMS gyroscope 140 overlying the CMOS surface region, andincludes an out-of-plane sense plate 121. Metal regions 151 and 152 areshields on the sides of the plate in the metal 6 layer, while 153 is theshield below the plate on the metal 4 layer.

It is also understood that the examples and embodiments described hereinare for illustrative purposes only and that various modifications orchanges in light thereof will be suggested to persons skilled in the artand are to be included within the spirit and purview of this applicationand scope of the appended claims.

What is claimed is:
 1. A system comprising an integrated MEMS gyroscopearchitecture, the system comprising: a substrate member having a surfaceregion; a CMOS IC layer overlying the surface region, the CMOS IC layerhaving a CMOS surface region, the CMOS IC layer having: a drive loop,the drive loop including a first Charge Sense Amplifier (CSA_DRV), afirst phase shifter (PS0), a first comparator, and an high-voltage (HV)driver; an Automatic Gain Control (AGC) loop circuit, the AGC loopcircuit including, the first comparator, a rectifier, aproportional-integral-derivative (PID) controller, the high-voltage (HV)driver, and a charge pump coupled in series in a loop, wherein an inputof the first comparator is coupled to the rectifier and an output of thefirst comparator is coupled to the HV driver; and a sense path having asecond Charge Sense Amplifier (CSA_SNS), a first Programmable GainAmplifier (PGA1), a mixer, a second Programmable Gain Amplifier (PGA2),a Low Pass Filter (LPF), an A/D converter (ADC), and digital processingcircuits; a MEMS gyroscope overlying the CMOS surface region, the MEMSgyroscope electrically coupled to the drive loop and the sense path, theMEMS gyroscope electrically coupled to the AGC loop circuit through thedrive loop; and metal shielding within a vicinity of the MEMS gyroscopeconfigured to reduce parasitic effects.
 2. The system of claim 1 furthercomprising a mixer coupled to the MEMS gyroscope, wherein the mixer isconfigured as a transmission gate.
 3. The system of claim 2 furthercomprising a circuit loop consisting of a digital low-pass-filter (LPF)coupled to a digital/analog converter (DAC), the circuit loop beingcoupled to the mixer.
 4. The system of claim 1 further comprising aprogrammable phase-shifter coupled to the comparator to adjust a phasedifference optimally to compensate for analog phase shifts.
 5. Thesystem of claim 1 wherein the charge pump is a first charge pump, andthe system further comprises a second charge pump, wherein the first andsecond charge pumps are configured to enable operation of the system atgreater voltages.
 6. A system comprising an integrated MEMS gyroscopearchitecture, the system comprising: a substrate member having a surfaceregion; a CMOS IC layer overlying the surface region, the CMOS IC layerhaving a CMOS surface region, the CMOS IC layer having: an AutomaticGain Control (AGC) loop circuit, the AGC loop circuit including arectifier, a comparator, a proportional-integral-derivative (PID)controller, a charge pump, a high-voltage (HV) driver, a drivecharge-sense-amplifier (CSA), and a 90 degrees phase shifter, wherein anoutput of the CSA is coupled to the 90 degree phase shifter, an outputof the 90 degree phase shifter is coupled to an input of the comparatorand is also coupled to the rectifier, an output of the comparator iscoupled to the HV driver, the PID controller receives an output from therectifier and a reference signal and generates an output in proportionto the difference of its input signals, and provide an output to controlthe gain of the HV driver; and a sense path having Charge SenseAmplifier (CSA_SNS), a Programmable Gain Amplifier (PGA1), a mixer,another Programmable Gain Amplifier (PGA2), a Low Pass Filter (LPF), anA/D converter (ADC), and digital processing circuits; and a MEMSgyroscope overlying the CMOS surface region, the MEMS gyroscopeelectrically coupled to the AGC loop circuit; and metal shielding withina vicinity of the MEMS gyroscope configured to reduce parasitic effects.7. The system of claim 6 further comprising a mixer coupled to the MEMSgyroscope, wherein the mixer is configured as a transmission gate. 8.The system of claim 7 further comprising a circuit loop including adigital low-pass-filter (LPF) coupled to a digital/analog converter(DAC), the circuit loop being coupled to the mixer or PGA2 toeffectively cancel dc offset or low frequency undesired artifacts. 9.The system of claim 6 further comprising a programmable phase-shifter(PS) coupled to the comparator.
 10. The system of claim 6 furthercomprising a programmable high-pass filter (HPF) having a cut offfrequency implemented using a DAC and a digital LPF in feedbackconfiguration.
 11. The system of claim 6 wherein the comparator is afirst comparator, and further comprising a quadrature mode circuitincluding a second comparator and a multiplexer, wherein the quadraturemode circuit is configured to monitor a quadrature signal from the MEMSgyroscope.
 12. The system of claim 6 further comprising a digital delaymodule coupled to the comparator and the HV driver, the digital delaymodule being configured to lock into a desired frequency.
 13. The systemof claim 6 further comprising metal shielding within a vicinity of theMEMS gyroscope, the metal shielding being configured to reduce parasiticeffects.
 14. A system comprising an integrated MEMS gyroscopearchitecture, the system comprising: a substrate member having a surfaceregion; a CMOS IC layer overlying the surface region, the CMOS IC layerhaving a CMOS surface region, the CMOS IC layer having: an AutomaticGain Control (AGC) loop circuit, the AGC loop circuit including arectifier, a comparator, a proportional-integral-derivative (PID)controller, a high-voltage (HV) driver, a drive charge-sense-amplifier(CSA_DRV), and a 90 degrees phase shifter, and a charge pump, wherein anoutput of the CSA_DRV is coupled to the 90 degree phase shifter, anoutput of the 90 degree phase shifter is coupled to an input of thecomparator and is also coupled to the rectifier, an output of thecomparator is coupled to the HV driver, the PID controller receives anoutput from the rectifier and a reference signal and generates an outputin proportion to the difference of its input signals, and provide anoutput to control the gain of the HV driver; a sense path having a senseCharge Sense Amplifier (CSA_SNS), a Programmable Gain Amplifier (PGA1),a mixer, another Programmable Gain Amplifier (PGA2), a Low Pass Filter(LPF), an A/D converter (ADC), and digital processing circuits; and aMEMS gyroscope overlying the CMOS surface region and electricallycoupled to the AGC loop circuit, the MEMS gyroscope including drivefeedback capacitors and sense capacitors, wherein the drive feedbackcapacitors are coupled to the drive CSA (CSA_DRV) and the sensecapacitors are coupled to the sense CSA (CSA_SNS); and metal shieldingwithin a vicinity of the MEMS gyroscope configured to reduce parasiticeffects.
 15. The system of claim 14 further comprising a supplyregulator coupled in series to a charge pump and to the MEMS gyroscope.16. The system of claim 14 wherein the CSA is a drive CSA, and furthercomprising a mixer coupled in series to a sense CSA and to the MEMSgyroscope, wherein the mixer is configured as a transmission gate andthe sense capacitors are coupled to the sense CSA.
 17. The system ofclaim 14 wherein the comparator is a first comparator, and furthercomprising a quadrature mode circuit including a second comparator and amultiplexer, wherein the quadrature mode circuit is configured tomonitor a quadrature signal from the MEMS gyroscope.
 18. The system ofclaim 14 further comprising a digital delay module coupled to thecomparator and the HV driver, the digital delay module being configuredto lock into a desired frequency.
 19. The system of claim 14 wherein theHV driver is implemented as a simple digital gate, wherein the chargepump provides a power supply to the HV driver, providing automatic gaincontrolled ac pulses to the MEMS gyroscope.
 20. The system of claim 14wherein the HV driver consists of a conventional external supply (VDD)at a desired voltage.